Devices for feeding originals in sheet form to and discharging them from an exposure window of a copy machine are well known; for example, U.S. Pat. Nos. 3,556,511 and 3,556,512 and United Kingdom Pat. No. 2,040,887. Generally, they comprise a holder for a pile of originals and a separator for taking originals from the pile one by one. A feed path is provided for guiding the originals from the pile to the exposure window of the copier which consists of a cooperating pair of rollers mounted in the feed path for conveying the originals in the feed path. A conveyor is provided which can be driven in a first direction for conveying the originals from the feed path to and over the exposure window and in the opposite, second, direction for removing the originals from the exposure window. The discharge path is used for returning the originals from the exposure window to the pile. A drive means is included which drives the pair of rollers in a direction in which the pair of rollers together with the conveyor device convey originals during or substantially during the periods of time in which the conveyor device is driven in the first direction.
In U.S. Pat. No. 3,556,512, for example, a device for changing originals in sheet form on an exposure window of a copying machine is described in which the feeder is provided with a first detector in the feed path between the pair of rollers and the conveyor device. In response to the passage of the leading edge of an original, this detector generates a signal which is used to stop the drive for the pair of rollers until a second detector in the discharge path has detected that the original to be changed has passed this second detector. During the conveyance of an original to and over the exposure window, the pair of rollers and the conveyor are driven in the same direction. To discharge the original, the direction of movement of the conveyor is reversed, but the pair of rollers move at a slower speed in the original direction until a new original has arrived at the first detector. To allow movement of the various elements at the correct times, a complex drive and detection system is used, in which the pair of rollers is alternately coupled to the conveyor and to the separator.
Another disadvantage of the known device is that the position in which an original is located after the drive of the pair of rollers has been stopped is not always the same, because uncontrollable inertia phenomena occur between the time of detection of the original and stopping of the rollers. In order to obtain a defined position of the original on the exposure window, an extra stop is used to overcome this problem.
Accordingly, an object of the present invention is to provide a simplified device means for feeding and discharging originals without reducing the possibilities of use. It is a further object of the present invention to provide an improvement in the prior art feeders without complicated drive and detection means.